Chemical gene damage carries across generations

Part of my job here at PAN is keeping track of the latest research about how pesticides are harming children’s health. This has kept me too busy of late, as studies seem to be coming fast and furious linking pesticides with childhood asthma, autism, birth defects, cancer and more.

One recent study gave me serious pause. We already understand that some chemicals can change how our genes function; now researchers know that this damage can be passed from one generation to the next. I’m no scientist, but I understand enough to know that compromising the DNA of future generations is not a good idea.

It’s been known for some time that a range of pollutants can strip or add chemical tags to DNA, locking the expression of these genes on or off and changing how they function. These changes are called “epigenetic tags,” and have been linked to various health effects including early puberty, disrupted ovarian function, and death of sperm-forming cells.

Overriding the reset button

What’s news from this recent study is that some chemicals can override the genetic “reset button” that usually protects a developing fetus from such changes.

In the normal course of things, any genetic changes parents have accumulated over the course of their lifetime are erased, and the genes go back to the original programming. A fascinating evolutionary trick.

But researchers at Washington State University in Pullman found that when pregnant rats were exposed to permethrin, DEET or any of a number of industrial chemicals (including common ingredients in plastics), the mother rats' great grand-daughters had higher risk of early puberty and malfunctioning ovaries — even though those subsequent generations had not been exposed to the chemical.

The study's leader, Dr. Michael Skinner, told Science News that every chemical tested resulted in these transgenerational effects, suggesting that "epigenetic changes are not some unique quirk of any one chemical," and that many pollutants likely have the potential to override the fetal reset button.

Cutting edge science

For me, these so-called "epigenetic effects" are hard to wrap my mind around. So I'm very much looking forward to a conference on the topic coming up later this month, sponsored by our partners at the Children's Environmental Health Network.

CEHN is pulling together an impressive cadre of researchers working to understand exactly how pollutants are compromising our DNA, how the damage gets passed along, and what it means for the health of future generations.

The Contribution of Epigenetics in Pediatric Environmental Health will be held here in San Francisco, May 30 – Jun 1. I'll be listening in, along with my PAN colleague (and fellow mom) Dr. Medha Chandra. We believe that the more we understand about how we are compromising the DNA of future generations with today's policies, the better case we can make that real change is needed, and soon. Hope to see you there.

is PAN's Program & Policy Director. With training in international policy and social change strategies, Kristin oversees PAN’s program work. She has been lead author on several PAN reports, with a particular emphasis on children’s health. She serves on the Policy Committee of the Children’s Environmental Health Network. Follow @KristinAtPAN